I eat fish sauce practically everyday but have never seen that brand. The best you can get here is the Viet Huong Three Crabs brand. I will ask the owner of the largest Dorchester VNmese grocery tomorrow, or tonite if see her son on FB. I will ask around in Orange County when I'm there next month.
was also looking for it a while back when I saw that episode none to be found around here Viet Huong Three Crabs seems to be the "go to" brand for viet style fish sauce around here, anyway prefer Tra Chang or Golden Boy for a Thai fish sauce